Scientific Collaboration Concludes Sea Lice from Farmed Salmon Not a Factor
Centre for Aquatic Health Sciences, Press Release December 13, 2010
Sea lice from salmon farms are no longer the prime suspect in the 2002 population crash of wild pink salmon in the Broughton Archipelago according to a study, “Relationship of farm salmon, sea lice, and wild salmon populations”, released today in the Proceedings of the National Academy of Sciences (PNAS).
The UC Davis study, a collaborative effort between researchers in California, Alaska and British Columbia, utilized data collection and research by BC Centre for Aquatic Health Sciences (BC CAHS) Executive Director, Sonja Saksida, in her capacity as an aquatic veterinarian, researcher and epidemiologist.
The paper’s lead author is Gary Marty, a veterinary pathologist and research associate at the UC Davis School of Veterinary Medicine. Drs. Marty and Saksida collaborated with Terrance Quinn who is a professor of fish population dynamics at the Juneau Center of the School of Fisheries and Ocean Sciences at the University of Alaska Fairbanks. Dr. Quinn, a respected authority on fish population modeling, did the statistical analysis.
Collection and analysis of the data, which took over two years, found no statistical correlation between lice levels on the farms and the survival of wild pink salmon populations. In particular, it found that sea lice from farmed salmon were not responsible for the 2002 population crash of wild pink salmon in the Broughton Archipelago.
This study differs from other published research as it includes industry information for 2000-2009 which provides a complete dataset for analysis. Saksida received permission from farmed salmon producing companies to access the data unconditionally – salmon farming companies conceded any role in the research direction, analysis and conclusions and agreed to release all data at publication.
Data from to 2003 to the present was not difficult to obtain since farms were required to monitor and report to a central database. However, data prior to 2003 was more difficult to locate as there was no standard method of collecting or storing at that time. As well, both companies that operated farms in the Broughton Archipelago pre-2003 no longer exist. Several key people who still work in salmon farming assisted in the discovery of the original paper files.
Regarding the study’s conclusion, Saksida states “The evidence shows that while farmed salmon are a main source of lice on individual juvenile pink salmon, wild populations are not affected. This is significant –it means that with regards to the British Columbia sea lice debate, farmed and wild salmon can coexist. It is now time to broaden our focus to identify the factors that are truly affecting our wild salmon populations.”
